Editing Complex system (section)

== Key concepts ==

=== Adaptation ===
[[Complex adaptive system]]s are special cases of complex systems that are [[Adaptive system|adaptive]] in that they have the capacity to change and learn from experience.<ref>{{cite book
| last = Holland
| first = John H.
| author-link = John Henry Holland
| date = 2014
| title = Complexity: A Very Short Introduction
| publisher = Oxford University Press
| isbn = 978-0-19-966254-8
| quote = All CAS agents, whatever their particularities, have three levels of activity: {{pb}} 1. Performance (moment-by-moment capabilities) {{pb}} 2. Credit-assignment (rating the usefulness of available capabilities) {{pb}} 3. Rule-discovery (generating new capabilities).}}</ref> Examples of complex adaptive systems include the international [[trade]] markets, social insect and [[ant]] colonies, the [[biosphere]] and the [[ecosystem]], the [[Human brain|brain]] and the [[immune system]], the [[Cell (biology)|cell]] and the developing [[embryo]], cities, [[Manufacturing|manufacturing businesses]] and any human social group-based endeavor in a cultural and [[social system]] such as [[Political party|political parties]] or [[Community|communities]].<ref>{{Cite journal |last1=Skrimizea |first1=Eirini |last2=Haniotou |first2=Helene |last3=Parra |first3=Constanza |year=2019 |title=On the 'complexity turn' in planning: An adaptive rationale to navigate spaces and times of uncertainty |journal=Planning Theory |volume=18 |pages=122–142 |doi=10.1177/1473095218780515 |s2cid=149578797 |doi-access=free}}</ref>

=== Decomposability ===
A system is '''decomposable''' if the parts of the system (subsystems) are independent from each other, for exemple the model of a [[perfect gas]] consider the relations among molecules negligeable.<ref name=":1">{{Cite journal |last=Simon |first=Herbert A. |date=1962 |title=The Architecture of Complexity |url=https://www.jstor.org/stable/985254 |journal=Proceedings of the American Philosophical Society |volume=106 |issue=6 |pages=467–482 |jstor=985254 |issn=0003-049X}}</ref> 

In a '''nearly decomposable''' system, the interactions between subsystems are weak but not negligeable, this is often the case in social systems.<ref name=":1" /> Conceptually, a system is nearly decomposable if the variables composing it can be separated into classes and subclasses, if these variables are independent for many functions but affect each other, and if the whole system is greater than the parts.<ref>{{Cite journal |last=Ostrom |first=Elinor |date=2007 |title=Sustainable Social-Ecological Systems: An Impossibility? |url=http://www.ssrn.com/abstract=997834 |journal=SSRN Electronic Journal |language=en |doi=10.2139/ssrn.997834 |issn=1556-5068|hdl=10535/3826 |hdl-access=free }}</ref>